1var str1 = "Hello ";
2var str2 = "world!";
3var res = str1.concat(str2);
4console.log(res);

1
2var str1 = "Hello ";
3var str2 = "world!";
4var res = str1.concat(str2);
5// does not change the existing strings, but
6// returns a new string containing the text
7// of the joined strings.

1//This method adds two or more strings and returns a new single string.
2
3let str1 = new String( "This is string one" ); 
4let str2 = new String( "This is string two" ); 
5let str3 = str1.concat(str2.toString());
6console.log("str1 + str2 : "+str3)
7
8output:
9str1 + str2 : This is string oneThis is string two

1const str1 = 'Hello';
2const str2 = 'World';
3
4console.log(str1.concat(' ', str2));
5// expected output: "Hello World"
6
7console.log(str2.concat(', ', str1));
8// expected output: "World, Hello"

1const txt = "My name is"
2console.log(`${txt} Paul`);

1let first_string = 'I am a programmer, ';
2let second_string = 'I am indisposable.';
3let what_i_said  = first_string + second_string;
4console.log(what_i_said);
5
6/* OR 
7*/
8
9let tell_my_boss = first_string.concat(second_string);
10console.log(tell_my_boss);